How to root 4.4.2 (DDUBNK1) topic

Hey all...
I was trying to root my grand 2 (4.4.2-build number: DDUBNK1)
I have downloaded all required files... But when i boot in download mode my phone shows

System status: official
Knox warranty void :0x0
Qualcomm secureboot: enable (csb)

So please tell me if i flash recovery will it increase knox counter and what do secureboot means???
How to disable knox??
Please guide me with correct method to root my phone... Thanks a lot

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